1. Field of the Invention
The present invention relates to a novel polypeptide and to a process for producing the same.
2. Description of the Prior Art
Among the endorphins which are brain peptides in mammals, beta-endorphin is a particularly important physiological peptide, exhibiting a variety of the physiologic activities, such as analgesic action, growth hormone secretion stimulating action, prolactin secretion stimulating action and neurotropic action. When administered by the intracerebral route, it exerts an analgesic effect in rats and mice [Science, Vol. 194, p. 630 (1976); Proceedings of the National Academy of Science of the United States of America, Vol. 73, No. 8, p. 2895 (1976), etc.].
Salmon endorphin, scientifically known as Oncorhynchus keta, has been isolated, and its chemical structure was recently elucidated by Kawauchi et al. The chemical structure has been identified as Acetyl-Tyr-Gly-Gly-Phe-Met-Lys-Pro-Tyr-Thr-Lys-Gln-Ser-His-Lys-Pro-Leu-Ile -Thr-Leu-Leu-Lys-His-Ile-Thr-Leu-Lys-Asn-Glu-Gln-OH. See Biochemical and Biophysical Research Communications, Vol. 88, No. 4, pages 1249-1254 (1979).